A new study found that people living in Multnomah County's poorest neighborhoods face a much greater risk of sudden cardiac arrest than people living in the wealthiest areas. For people younger than 65, residents from the poor neighborhoods were more than twice as likely to have their heart suddenly stop than people living in the rich ones. The study, published in the journal Resuscitation, examined 714 sudden cardiac arrests logged in Multnomah County from Feb. 1, 2002, to Jan. 31, 2004. Each victim's home address was matched to a census tract. Researchers then divided the tracts into four groups, ranking by four measures of social status — median income, median home value, percent of residents below the poverty line and percent of residents with a bachelor's degree or more education. "Depending on which of the four measures you used, (cardiac arrest) incidence was 30 to 80 percent higher in the lowest quartile," said Kyndaron Reinier, the paper's first author. Victims under 65 showed a bigger gap. The poorest quartile had 80 percent to 170 percent more risk for sudden cardiac arrest. In seniors, the three lowest quartiles had similar risks, and the wealthiest quartile had slightly lower risk. Cardiac arrest is a problem with the heart's rhythm that causes it to stop, starving the brain of blood. It's different from and deadlier than a heart attack, in which blood vessels feeding the heart clog up and only parts of the heart lose their blood supply. Though the study showed that poor people had an increased risk of cardiac arrest, it could not explain why. "We haven't got it figured out, but we'd love to figure it out," said Sumeet Chugh, M.D., the Oregon Health & Science University cardiologist who led the study. Chugh said poorer people could get less health care, or have more problems managing conditions that can lead to cardiac arrest, such as high blood pressure, coronary artery disease and diabetes. "It is clear from these findings," said Chugh, "that socioeconomic status matters in the incidence of sudden cardiac arrest as it does for many other diseases. However, there exists a uniform 9-1-1 response standard for all regions within the county, which would suggest that additional interventions are necessary to both prevent the higher rates of sudden cardiac arrest observed in poorer neighborhoods as well as improve the outcomes." The findings, said Chugh, also have immediate implications for the deployment of automated external defibrillators, machines that can shock some stopped hearts back to life, which are increasingly found in high-density public places like airports. "Common sense would tell you to go with population density, but these findings would say you should also look at socioeconomic status to determine the most optimal placement of defibrillators in the community," Chugh said.